A packet of cigarettes normally comprises an inner package comprising a group of cigarettes wrapped in a sheet of inner wrapping; and an outer package enclosing the inner package, and which may be cup-shaped and comprise a sheet of outer wrapping folded about the inner package (soft packet of cigarettes), or may comprise a rigid, hinged-lid box formed by folding a rigid blank about the inner package (rigid packet of cigarettes).
Folding the sheet of inner wrapping about the group of cigarettes has been found to damage the ends of the cigarettes by producing local deformation (at both the filter-tipped end and the plain end) and/or tobacco fallout (i.e. loss of tobacco, obviously only from the plain tips at the opposite end to the filters). Damage by folding the sheet of inner wrapping about the group of cigarettes mostly applies to the cigarettes at the corners of the group, but is nevertheless evident in all the outer cigarettes, i.e. located along the fold lines of the sheet of inner wrapping. Moreover, the stiffness of the sheet of inner wrapping deforms the ends of the cigarettes, thus resulting in an inner package with rounded as opposed to square edges. This is particularly undesirable by producing an overall look of the exposed portion of the inner package that is not very popular with consumers, who tend to opt for inner packages with sharp, well pronounced edges.
Tobacco is highly sensitive to environment. That is, in contact with the atmosphere, its organic characteristics tend to vary alongside variations in humidity (by losing or absorbing too much moisture) or due to evaporation of the volatile substances with which the tobacco is impregnated (especially in the case of aromatic cigarettes treated with spices such as cloves). To preserve the tobacco, a rigid packet of cigarettes has been proposed, in which the inner package is airtight and comprises a sheet of airtight, heat-seal wrapping. Folding a sheet of airtight inner wrapping, however, is particularly damaging to the cigarettes, by being thicker (and therefore stiffer) than conventional sheets of foil inner wrapping.